Polymer compound, method of producing the same, photosensitive composition, and pattern formation method

ABSTRACT

The present invention provides a cross-linkable polymer compound which can be developed with an aqueous developer and exhibits excellent patterning properties; a photosensitive composition containing the same; and a pattern formation method employing the composition. The polymer compound containing monomer units represented by formulas (I) to (III):  
                 
 
     wherein each of R 1  to R 4  is hydrogen and/or a methyl group; p represents an integer between 1 to 10 inclusive; X represents hydrogen, an alkali metal, or an ammonium represented by formula (1):  
                 
 
     wherein each of R 5  to R 8  represents hydrogen, a C1-C3 alkyl group, or a C1-C3 alkanol group; and a plurality of Xs may be the same or different from one another, the compositional proportions of the monomer units falling within the following ranges: 2 mol %≦1≦73 mol %; 8 mol %≦m≦83 mol %; and 15 mol %≦n≦80 mol %.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a polymer compound serving as acomponent of a negative-type photosensitive composition, and to aphotosensitive composition containing the compound. In particular, theinvention relates to a polymer compound which can be developed with anaqueous developer and exhibits excellent patterning properties, and to aphotosensitive composition containing the compound.

[0003] 2. Background Art

[0004] There have been known, as photosensitive compositions containedin a photopolymerization-type resist developable with an aqueousdeveloper, compositions comprising a carboxyl-group-containing acrylicor methacrylic copolymer to which is added an acrylate monomer or amethacrylate monomer (hereinafter acrylic acid and methacrylic acid arecollectively referred to as (meth)acrylic acid, and acrylate andmethacrylate are collectively referred to as (meth)acrylate). Thesephotosensitive compositions have been developed from various aspects andemployed in a variety of fields. For example, Japanese PatentApplication Laid-Open (kokai) Nos. 9-236917 and 9-249823 disclose thatsuch photosensitive compositions find use as photoetching resistsemployed in steps for producing printed wiring boards.

[0005] However, these resists, having poor solubility in water, aredeveloped with an alkaline solution, and such alkaline developers mustbe handled carefully. In addition, in order to enhance hardness of curedproducts thereof, there must be added a (meth)acrylate monomer, which isgenerally a strong skin-irritant and inflammable. This also makes thehandling thereof difficult, and the monomers are not preferablyemployed.

SUMMARY OF THE INVENTION

[0006] The present inventors have found that a polymer compound producedby adding glycidyl (meth)acrylate in a predetermined amount to acopolymer comprising at least (meth)acrylic acid and at least one of2-hydroxyethyl (meth)acrylate and polyoxyethylene mono(meth)acrylate canbe developed with water, exhibits excellent adhesion to a substrate, andhas excellent acid resistance. The present invention has beenaccomplished on the basis of this finding.

[0007] Accordingly, in a first aspect of the present invention, there isprovided a polymer compound containing monomer units represented byformulas (I) to (III):

[0008] wherein each of R₁ to R₄ is hydrogen and/or a methyl group; prepresents an integer between 1 to 10 inclusive; X represents hydrogen,an alkali metal, or an ammonium represented by formula (1):

[0009] wherein each of R₅ to R₈ represents hydrogen, a C1-C3 alkylgroup, or a C1-C3 alkanol group; and a plurality of Xs may be the sameor different from one another,

[0010] the compositional proportions of the monomer units falling withinthe following ranges:

[0011] 2≦mol %≦1≦73 mol %; 8 mol %≦m 83 mol %; and 15 mol %≦n≦80 mol %.

[0012] Preferably, the polymer compound according to the first aspect ofthe present invention also contains a monomer unit other than monomerunits represented by formula (I) to (III) in an amount of 10 mol % orless.

[0013] In a second aspect of the present invention, there is provided amethod of producing a polymer compound containing monomer unitsrepresented by the aforementioned formula (I) to (III), thecompositional proportions of the monomer units falling within thefollowing ranges:

[0014] 2 mol %≦1≦73 mol %; 8 mol %≦m≦83 mol %; and 15 mol %≦n≦80 mol %,comprising adding glycidyl (meth)acrylate in a predetermined amount to acopolymer comprising at least (meth)acrylic acid and at least one of2-hydroxyethyl (meth)acrylate and polyoxyethylene mono(meth)acrylate.

[0015] Preferably, in the method of producing a polymer compoundaccording to the second aspect of the invention, at least one of anN-nitrosophenylhydroxylamine ammonium salt and4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl is employed as apolymerization inhibitor.

[0016] In a third aspect of the present invention, there is provided aphotosensitive composition containing, as a component, a polymercompound as recited in the first aspect of the invention.

[0017] Preferably, the photosensitive composition according to the thirdaspect of the invention contains water as a solvent.

[0018] Preferably, the photosensitive composition according to the thirdaspect of the invention contains a polymerizable monomer.

[0019] Preferably, the photosensitive composition according to the thirdaspect of the invention contains a colorant.

[0020] Preferably, the photosensitive composition according to the thirdaspect of the invention contains at least one of a photopolymerizationinitiator and a photosensitizer.

[0021] In a fourth aspect of the present invention, there is provided apattern formation method comprising forming a coating film by use of aphotosensitive composition as recited in the third aspect of theinvention and developing by use of water; i.e., a neutral developer.

[0022] In view of the foregoing, an object of the present invention isto provide a polymer compound producing a photosensitive compositionwhich is less flammable, can be handled easily, can be developed withwater, and can attain high resolution without incorporating anadditional monomer. Another object of the present invention is toprovide a photosensitive composition containing the polymer compound.Still another object of the invention is to provide a pattern formationmethod.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0023] The polymer compound of the present invention contains thermallycurable monomer units (I) and (II), which undergo thermal cross-linkingreaction, and photocurable monomer unit (III) in combination.

[0024] No particular limitation is imposed on the bonding manner betweenthe monomer units so long as the polymer compound of the presentinvention contains the units represented by (I), (II), and (III), andthe polymer compound may be any type of polymer such as a randomcopolymer, an alternating copolymer, a block copolymer, or a graftcopolymer.

[0025] The preferred compositional proportions (the aforementioned l, m,and n) of units (I) to (III) contained in the polymer compound of thepresent invention are 2 mol %≦1≦73 mol %; 8 mol %≦m≦83 mol %; and 15 mol%≦n≦80 mol %, respectively. When the proportion “l” is considerably low,thermal curability—one characteristic of the polymer compound of thepresent invention—cannot be attained, whereas when the proportion “l”,is excessively high, the amounts of other monomer units decrease,failing to attain sufficient photosensitivity. When the proportion “m”is considerably low, required developability and water-solubility cannotbe attained, whereas when the proportion is excessively high, waterresistance of cured products thereof decreases. When the proportion “n”is considerably low, required developability cannot be attained, whereaswhen the proportion is excessively high, the amounts of other monomerunits decrease, failing to attain required developability,water-solubility, and thermal curability. The parameter “p” is generally1 to 10. However, when “p” is in excess of 10, both resolution of thephotosensitive composition containing the compound and water resistanceof cured products thereof decrease.

[0026] Other than monomer units (I) to (III), the polymer compound mayor may not contain another copolymerizable component. The preferredamount of the copolymerizable component is less than 10 mol % so as notto affect adhesion of the polymer compound and physical properties ofthe cured composition.

[0027] Examples of other copolymerizable components include unsaturatedorganic acids such as maleic acid and anhydrides thereof;(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate,benzyl (meth)acrylate, and hydroxypropyl (meth)acrylate; acrylamidessuch as N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide,N-methylolacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide,N-isopropylmethacrylamide, N-methylolmethacrylamide,N,N-dimethylacrylamide, N,N-diethylacrylamide,N,N-dimethylmethacrylamide, and N,N-diethylmethacrylamide; styrenes suchas styrene and hydroxystyrene; N-vinylpyrrolidone; N-vinylformamide;N-vinylacetamide; and N-vinylimidazole.

[0028] Preferably, the polymer compound of the present invention issynthesized through polymerization in a solvent in the presence of apolymerization initiator. Although the solvent to be employed is notparticularly limited, it preferably has a composition allowing thepolymer compound of the present invention to be dissolved therein.

[0029] Examples of solvents include water; ethylene glycols such asethylene glycol, diethylene glycol, triethylene glycol, andtetraethylene glycol; glycol ethers such as ethylene glycol monomethylether, diethylene glycol monomethyl ether, ethylene glycol diethylether, and diethylene glycol dimethyl ether; glycol ether acetates suchas ethylene glycol monoethyl ether acetate, diethylene glycol monoethylether acetate, and diethylene glycol monobutyl ether acetate; propyleneglycols such as propylene glycol, dipropylene glycol, and tripropyleneglycol; propylene glycol ethers such as propylene glycol monomethylether, propylene glycol monoethyl ether, dipropylene glycol monomethylether, dipropylene glycol monoethyl ether, propylene glycol dimethylether, dipropylene glycol dimethyl ether, propylene glycol diethylether, and dipropylene glycol diethyl ether; propylene glycol etheracetates such as propylene glycol monomethyl ether acetate, propyleneglycol monoethyl ether acetate, dipropylene glycol monomethyl etheracetate, and dipropylene glycol monoethyl ether acetate;dimethylsulfoxide; N-methylpyrrolidone; dimethylformamide,dimethylacetamide, and mixtures thereof.

[0030] The solvent is preferably employed in an amount such that theamount of the polymer compound in the solution is controlled to 5-70 wt.%, more preferably 20-60 wt. %. When the amount is 5 wt. % or less, thepolymerization rate is low, and unreacted residual monomers possiblyremain, whereas when the amount is 70 wt. % or more, the viscosity ofthe resultant solution increases, disadvantageously causing difficulthandling and reaction-rate-control of the solution.

[0031] Any known polymerization initiators, such as thermalpolymerization initiators, photopolymerization initiators, and redoxpolymerization initiators may be used. However, radical polymerizationinitiators such as peroxides and azo compounds are preferred, in view ofeasy handling and controllability of reaction rate and molecular weight.

[0032] Examples of peroxide type polymerization initiators includemethyl ethyl ketone peroxide, cyclohexanone peroxide,methylcyclohexanone peroxide, acetylacetone peroxide, methylacetoacetate peroxide,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,1,1-bis(tert-butylperoxy)cyclohexane,1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane,1,1-bis(tert-hexylperoxy)cyclohexane,1,1-bis(tert-butylperoxy)cyclododecane, isobutyryl peroxide, lauroylperoxide, succinyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoylperoxide, octanoyl peroxide, stearoyl peroxide, diisopropylperoxydicarbonate, di-n-propylperoxy dicarbonate, di-2-ethylhexylperoxydicarbonate, di-2-ethoxyethylperoxy dicarbonate, di-2-methoxybutylperoxydicarbonate, bis(4-tert-butylcyclohexyl)peroxy dicarbonate,(α,α-bis-neodecanoylperoxy)diisopropylbenzene, cumyl peroxyneodecanoate,octyl peroxyneodecanoate, hexyl peroxyneodecanoate, tert-butylperoxyneodecanoate, tert-hexyl peroxypivalate, tert-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane,1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butylperoxy-3-methylpropionate, tert-butyl peroxylaurate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-hexylperoxyisopropylmonocarbonate, tert-butylperoxyisopropyl carbonate,2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peracetate,tert-hexyl perbenzoate, and tert-butyl perbenzoate. These peroxides maybe combined with a reducing agent so as to provide redox initiatorsystems.

[0033] Examples of azo type polymerization initiators include1,1-azobis(cyclohexane-1-carbonitrile),2,2′-azobis(2-methyl-butyronitrile), 2,2′-azobisisobutyronitrile,2,2′-azobis(2,4-dimethyl-valeronitrile),2,2′-azobis(2,4-dimethyl-4-methoxyvaleronitrile),2,2′-azobis(2-amidino-propane) hydrochloride,2,2′-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]hydrochloride,2,2′-azobis[2-(2-imidazolin-2-yl)propane]hydrochloride,2,2′-azobis[2-(5-methyl-2-imidazolin-2-yl)propane],2,2′-azobis{2-methyl-N-[1,1-bis(2-hydroxymethyl)-2-hydroxyethyl]propionamide},2,2′-azobis[2-methyl-N-(2-hydroxyethyl)propionamide],2,2′-azobis(2-methylpropionamide) dihydrate, 4,4′-azobis(4-cyanovalericacid), 2,2′-azobis(2-hydroxymethylpropionitrile), 2,2′-azobis(2-methylpropionic acid) dimethyl ester (dimethyl2,2′-azobis(2-methylpropionate)) (V-601, product of Wako Pure ChemicalIndustries, Ltd.), and cyano-2-propylazoformamide.

[0034] In addition to the aforementioned peroxide-type initiators andazo-type initiators, known molecular-weight-controlling agents such as achain transfer agent, a chain terminating agent, and a polymerizationaccelerator may be incorporated in order to attain a molecular weightfalling within a preferable range.

[0035] To the thus-synthesized polymer compound, a catalyst, a solvent,and a polymerization inhibitor for suppressing polymerization of(meth)acryloyl groups are added in accordance with needs. The mixture isheated for a predetermined time, performing addition of glycidyl(meth)acrylate.

[0036] Examples of catalysts include amines such as pyridine, quinoline,imidazole, N,N-dimethylcyclohexylamine, triethylamine,N-methylmorpholine, N-ethylmorpholine, triethylenediamine,N,N-dimethylaniline, N,N-dimethylbenzylamine, andtris(N,N-dimethylaminomethyl)phenol; quaternary ammonium compounds suchas tetramethylammonium chloride, tetramethylammonium bromide,trimethylbenzylammonium chloride, and tetramethylammonium hydroxide;tributylphosphine; and triphenylphosphine.

[0037] Examples of polymerization inhibitors include hydroquinone,hydroquinone monomethyl ether, t-butylhydroquinone, t-butylcatechol,N-methyl-N-nitrosoaniline, N-nitrosophenylhydroxylamine ammonium salt(Q-1300, product of Wako Pure Chemical Industries, Ltd.),N-nitrosophenylhydroxylamine aluminum salt (Q-1301, product of Wako PureChemical Industries, Ltd.), 2,2,6,6-tetramethylpiperidin-1-oxyl, and4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl. Of these,N-nitrosophenylhydroxylamine ammonium salt and4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl are particularlypreferred.

[0038] In order to enhance water-solubility and developability, thethus-synthesized polymer compound may be neutralized with an inorganicalkaline compound or an organic amine or ammonium. Examples of inorganicalkaline compounds include alkali metal hydroxides such as caustic soda.Examples of organic amines include alkylamines such as triethylamine;and alkylalkanolamines such as dimethylaminoethanol. Examples of organicammoniums include ammonium hydroxide, methylammonium hydroxide,dimethylammonium hydroxide, trimethylammonium hydroxide, andtetramethylammonium hydroxide (TMAH).

[0039] The suitable neutralization degree varies depending on theproperties of the polymer compound such as the composition, molecularweight, target water solubility, and developability. Thus, theneutralization degree may be appropriately predetermined in accordancewith purposes.

[0040] The thus-synthesized polymer compound may be isolated in the formof a solid so as to effect purification, storage, changing the solvent,etc. By use of the solid form polymer compound, a photosensitivecomposition free of organic solvent can be provided. No particularlimitation is imposed on the method of isolation, and methods such asspray drying, film drying, dropwise addition to a poor solvent, andre-precipitation may be employed.

[0041] In order to formulate a photosensitive composition by use of thethus-synthesized polymer compound, a photopolymerization initiatorand/or a photosensitizer is preferably added. These compounds may bedissolved or dispersed in a solvent, followed by addition to thecomposition. Alternatively, these compounds may be chemically linked tothe polymer compound.

[0042] No particular limitation is imposed on the employedphotopolymerization initiators and photosensitizers. Examples includebenzophenones such as benzophenone, 4-hydroxybenzophenone,bis-N,N-dimethylaminobenzophenone, bis-N,N-diethylaminobenzophenone, and4-methoxy-4′-dimethylaminobenzophenone; thioxanthones such asthioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone,chlorothioxanthone, and isopropoxychlorothioxanthone; anthraquinonessuch as ethylanthraquinone, benzanthraquinone, aminoanthraquinone,chloroanthraquinone, anthraquinone-2-sulfonate salts, andanthraquinone-2,6-disulfonate salts; acetophenones; benzoine ethers suchas benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether;2,4,6-trihalomethyltriazines; 1-hydroxycyclohexyl phenyl ketone;2,4,5-triarylimidazole dimers such as2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer, and2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer; benzyl dimethylketal; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one;2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone;2-hydroxy-2-methyl-1-phenyl-propan-1-one,1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one;phenanthrequinone; 9,10-phenanthrequinone; benzoins such asmethylbenzoin and ethylbenzoin; acridine derivatives such as9-phenylacridine and 1,7-bis(9,9′-acridinyl)heptane; bisacylphosphineoxides; and mixtures thereof.

[0043] In addition to these photopolymerization initiators and/orphotosensitizers, other additives such as an accelerator may be furtheradded. Examples include ethyl p-dimethylaminobenzoate, isoamylp-dimethylaminobenzoate, N,N-dimethylethanolamine,N-methyldiethanolamine, and triethanolamine.

[0044] By adding a polymerizable monomer, the sensitivity, resistance tochemicals, heat resistance, and mechanical strength of thephotosensitive composition of the present invention can be enhanced.Such a polymerizable monomer may also be added so as to control the flowcharacteristics of the composition. The type of the monomers cannot bedefinitely fixed, and in accordance with use and purposes of thecomposition to be applied, appropriate selection of polymerizablemonomers is required. Examples of monomers include polyethylene glycoldi(meth)acrylate (the number of EO units: 2-14), trimethylolpropanedi(meth)acrylate, trimethylolpropane tri(meth)acrylate,trimethylolpropanethoxy tri(meth)acrylate, trimethylolpropanepropoxytri(meth)acrylate, tetramethylolmethane tri(meth)acrylate,tetramethylolmethane tetra(meth)acrylate, polypropylene glycoldi(meth)acrylate (the number of PO units: 2-14), dipentaerythritolpenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, bisphenol Apolyoxyethylene di(meth)acrylate, bisphenol A dioxyethylenedi(meth)acrylate, bisphenol A trioxyethylene di(meth)acrylate, andbisphenol A decaoxyethylene di(meth)acrylate; esters obtained from apolyvalent carboxylic acid (e.g., phthalic anhydride) and a compoundhaving a hydroxyl group and an ethylenic unsaturated group (e.g.,β-hydroxyethyl (meth)acrylate; alkyl (meth)acrylates such as methyl(meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and2-ethylhexyl (meth)acrylate; (meth)acrylic acid adducts of epoxycompounds such as ethylene glycol diglycidyl ether, diethylene glycoldiglycidyl ether, triethylene glycol diglycidyl ether, tetraethyleneglycol diglycidyl ether, polyethylene glycol diglycidyl ether, propyleneglycol diglycidyl ether, dipropylene glycol diglycidyl ether,tripropylene glycol diglycidyl ether, tetrapropylene glycol diglycidylether, polypropylene glycol diglycidyl ether, sorbitol triglycidylether, and glycerin triglycidyl ether, unsaturated organic acids such asmaleic acid and anhydrides thereof; (meth)acrylates such as methyl(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl(meth)acrylate, butyl (meth)acrylate, benzyl (meth)acrylate, andhydroxypropyl (meth)acrylate; acrylamides such as N-methylacrylamide,N-ethylacrylamide, N-isopropylacrylamide, N-methylolacrylamide,N-methylmethacrylamide, N-ethylmethacrylamide,N-isopropylmethacrylamide, N-methylolmethacrylamide,N,N-dimethylacrylamide, N,N-diethylacrylamide,N,N-dimethylmethacrylamide, and N,N-diethylmethacrylamide; styrenes suchas styrene and hydroxystyrene; N-vinylpyrrolidone; N-vinylformamide;N-vinylacetamide; N-vinylimidazole; and mixtures thereof.

[0045] By adding a colorant, halation of the photosensitive compositioncaused by a substrate surface and dispersible additives can be reduced,to thereby enhance resolution. The type of colorants to be added cannotbe definitely fixed, and appropriate selection of the colorants isrequired, in accordance with the material of a substrate onto which apattern is formed and the photopolymerization initiator to be applied.Examples of colorants include dyes formed of species such asphthalocyanine, anthraquinone, azo, indigo, coumarine, andtriphenylmethane; pigments formed of species such as phthalocyanine,anthraquinone, azo, quinacridone, coumarine, and triphenylmethane; andmixtures thereof. These colorants may also be added so as to facilitatevisual inspection of products.

[0046] The photosensitive composition of the present invention may beformed into a solution or paste. A solvent may be added so as to form asolution or paste. Such a solvent is not particularly limited, andexamples include water; ethylene glycols such as ethylene glycol,diethylene glycol, triethylene glycol, and tetraethylene glycol; glycolethers such as ethylene glycol monomethyl ether, diethylene glycolmonomethyl ether, ethylene glycol diethyl ether, and diethylene glycoldimethyl ether; glycol ether acetates such as ethylene glycol monoethylether acetate, diethylene glycol monoethyl ether acetate, and diethyleneglycol monobutyl ether acetate; propylene glycols such as propyleneglycol, dipropylene glycol, and tripropylene glycol; propylene glycolethers such as propylene glycol monomethyl ether, propylene glycolmonoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycolmonoethyl ether, propylene glycol dimethyl ether, dipropylene glycoldimethyl ether, propylene glycol diethyl ether, and dipropylene glycoldiethyl ether; propylene glycol ether acetates such as propylene glycolmonomethyl ether acetate, propylene glycol monoethyl ether acetate,dipropylene glycol monomethyl ether acetate, and dipropylene glycolmonoethyl ether acetate; dimethylsulfoxide; N-methylpyrrolidone;dimethylformamide, dimethylacetamide, and mixtures thereof. Thephotosensitive composition preferably contains water, in considerationof problems such as safety of operation circumstances and flammability.

[0047] Into the photosensitive composition of the present invention,other known components such as a polymerization inhibitor, aplasticizer, a defoaming agent, and a coupling agent may be incorporatedin accordance with needs.

[0048] The aforementioned compositional proportions in thephotosensitive composition of the present invention cannot be definitelyfixed, and appropriate values vary depending on conditions such as thecomposition of the polymer compound, type of monomers, and productionsteps such as method of application and light-exposure of thecomposition. However, the compositional proportions can be predeterminedin accordance with purposes. For example, the following compositionalrange is preferred: Polymer compound: 1-95 wt. % Photopolymerizationinitiator and photosensitizer: 0.02-30 wt. % Water: 2-96 wt. %Polymerizable monomer(s): 0-60 wt. % Colorant(s): 0-50 wt. %.

[0049] The photosensitive composition of the present invention isapplied as a solution or a paste. No particular limitation is imposed onthe method for applying the composition, and a variety of coatingmethods such as screen printing, curtain coating, blade coating, spincoating, spray coating, dip coating, and slit coating may be employed.

[0050] The thus-applied solution or paste is dried and then exposed toUV rays or an electron beam through a specific mask.

[0051] The exposed coating is developed in a wet manner, to thereby forma pattern.

[0052] Any developing method may be employed, such as development bymeans of a spray, paddles, or dipping. Particularly, development bymeans of a spray is preferred, in view of generation of a small amountof developer waste. Ultrasound may be applied if required.

[0053] Although the developer is preferably water; i.e., a neutraldeveloper, a weakly acidic or alkaline developer may also be employed.Additives such as an organic solvent, a surfactant, and a defoamingagent may be added so as to enhance performance of the developer.

EXAMPLES

[0054] The present invention will next be described in detail by way ofexamples, which should not be construed as limiting the inventionthereto, as the photosensitive compositions comprising the polymercompound of the invention come in a variety of types and have variouspurposes of use.

Synthesis Example 1

[0055] 2-Hydroxyethyl acrylate (43.5 g), methacrylic acid (130.5 g), anddimethyl 2,2′-azobis(2-methylpropionate) (V-601, product of Wako PureChemical Industries, Ltd.) (6.8 g) were dissolved in propylene glycol(87.0 g) to form a solution. The solution was added dropwise topropylene glycol (457.4 g) under nitrogen flow over two hours, while thepropylene glycol was maintained at 80° C. The resultant mixture was agedfor four hours under the same conditions. Subsequently, the temperatureof the mixture was elevated to 100° C. for reaction, and the heatedmixture was aged for two hours, forming a transparent viscous polymersolution. The polymer solution was cooled again to 80° C. To the cooledmixture, pyridine (13.0 g) and an N-nitrosophenylhydroxylamine ammoniumsalt (Q-1300, product of Wako Pure Chemical Industries, Ltd.) (0.6 g)dissolved in propylene glycol (32.0 g) were individually added. Then,glycidyl methacrylate (116.0 g) was added dropwise to the resultantmixture over 30 minutes, and the reaction mixture was maintained at 80°C. for a further six hours, to thereby obtain a pale-red viscous polymersolution (A).

[0056] Unreacted monomers contained in the thus-obtained polymersolution (A) were quantitatively determined through high-performanceliquid chromatography to thereby calculate the balance (mol %) ofmonomers (I) to (III) in the polymer, and the results revealed that l,m, and n were 13.7 mol %, 56.5 mol %, and 29.8 mol %, respectively. Thepolymer solution had an acid value of 100 mg-KOH/g and an unsaturationequivalent of 1.4 meq/g.

Synthesis Example 2

[0057] The polymer solution (A) (100 g) which had been produced inSynthesis Example 1 was added dropwise to ethyl acetate (1000 ml) placedin a vessel equipped with an agitator, to effect dispersion for onehour. The resultant matter was separated through filtration and dried,to thereby obtain a white powder (B).

Synthesis Example 3

[0058] 2-Hydroxyethyl acrylate (60.0 g), acrylic acid (180.0 g), anddimethyl 2,2′-azobis(2-methylpropionate) (V-601, product of Wako PureChemical Industries, Ltd.) (2.0 g) were dissolved in propylene glycol(63.0 g), to form a solution. The solution was added dropwise topropylene glycol (356.9 g) under nitrogen flow over two hours, while thepropylene glycol was maintained at 80° C. The resultant mixture was agedfor four hours under the same conditions. Subsequently, the temperatureof the mixture was elevated to 100° C. for reaction, and the heatedmixture was aged for two hours, forming a transparent viscous polymersolution. The polymer solution was cooled again to 80° C. To the cooledmixture, pyridine (17.8 g) and an N-nitrosophenylhydroxylamine ammoniumsalt (Q-1300, product of Wako Pure Chemical Industries, Ltd.) (0.4 g)dissolved in propylene glycol (32.0 g) were individually added. Then,glycidyl methacrylate (160.0 g) was added dropwise to the resultantmixture over 30 minutes, and the reaction mixture was maintained at 80°C. for a further six hours, to thereby obtain a pale-red viscous polymersolution (C).

[0059] Unreacted monomers contained in the thus-obtained polymersolution (C) were quantitatively determined through high-performanceliquid chromatography to thereby calculate the balance (mol %) ofmonomers (I) to (III) in the polymer, and the results revealed that l,m, and n were 12.4 mol %, 61.3 mol %, and 26.3 mol %, respectively. Thepolymer solution had an acid value of 48.2 mg-KOH/g and an unsaturationequivalent of 0.96 meq/g.

Comparative Synthesis Example 1

[0060] A solution containing methyl methacrylate (80.0 g), isobutylmethacrylate (5.0 g), acrylic acid (15.0 g), and dimethyl2,2′-azobis(2-methylpropionate) (V-601, product of Wako Pure ChemicalIndustries, Ltd.) (0.7 g) was added dropwise to the diethylene glycolmono buthyl ether (65.0 g) under nitrogen flow over five hours, whilethe diethylene glycol mono buthyl ether was maintained at 80° C. Theresultant mixture was aged for one hour under the same conditions.Subsequently, the temperature of the mixture was elevated to 100° C. forreaction, and the heated mixture was aged for two hours, forming atransparent viscous polymer solution. The polymer solution was cooledagain to 80° C. To the cooled mixture, pyridine (1.5 g) and hydroquinone(0.2 g) serving as a polymerization inhibitor were individually added.Then, glycidyl methacrylate (15.0 g) was added dropwise to the resultantmixture over 30 minutes, and the reaction mixture was maintained at 80°C. for a further six hours, to thereby obtain a pale-red viscous polymersolution (D).

[0061] Unreacted monomers contained in the thus-obtained polymersolution (D) were quantitatively determined through high-performanceliquid chromatography to thereby calculate the balance (mol %) ofmonomers (I) to (III) in the polymer, and the results revealed that l,m, and n were 0 mol %, 17.7 mol %, and 9.2 mol %, respectively. Thepolymer solution had an acid value of 34.0 mg-KOH/g and an unsaturationequivalent of 0.65 meq/g.

Example 1

[0062] To the polymer solution (A) (100 g) which had been obtained inSynthesis Example 1, a 10% aqueous solution (2.7 g) of NaOH serving asan alkali agent for neutralization;1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one(Irgacure 2959, product of Ciba Specialty Chemicals) (1.8 g) serving asa photopolymerization initiator; and ion-exchange water (65 g) wereadded, to thereby prepare a photosensitive composition.

[0063] The thus-prepared photosensitive composition was applied to ametal substrate by means of a spin-coater and dried in a clean oven at80° C. for 20 minutes, followed by cooling to room temperature. Thecoating was exposed to ultraviolet light from an ultra-high-pressuremercury lamp having an illuminance of 2.5 mW/cm² for a dose of 1350mJ/cm², through a mask having a predetermined pattern. Subsequently, thephotocured polymer was spray-developed with ion-exchange water for 30seconds, to thereby obtain an objective pattern. The pattern had a filmthickness of 5 μm and a resolution of 10 μm, and the sensitivity of thecomposition as evaluated on the basis of the UGRA step tablet was 5.

[0064] The photosensitive composition was stored at 40° C., andvariation in patterning characteristics were evaluated. The resultsindicated that no variation in patterning characteristics were observedeven after the composition had been stored for two weeks. Thephotosensitive composition was subjected to flash point measurement in aCleveland-open manner, and the results indicated that no flash point wasidentified.

Example 2

[0065] To the white powder (B) (35 g) which had been obtained inSynthesis Example 2, a 10% aqueous solution (2.7 g) of NaOH serving asan alkali agent for neutralization;1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one(Irgacure 2959, product of Ciba Specialty Chemicals) (1.8 g) serving asa photopolymerization initiator; and ion-exchange water (130 g) wereadded. The powder was sufficiently dissolved into the solution, tothereby prepare a photosensitive composition.

[0066] The thus-prepared photosensitive composition was applied to ametal substrate by means of a spin-coater and dried in a clean oven at80° C. for 20 minutes, followed by cooling to room temperature. Thecoating was exposed to ultraviolet light from an ultra-high-pressuremercury lamp having an illuminance of 2.5 mW/cm² for a dose of 1350mJ/cm², through a mask having a predetermined pattern. Subsequently, thephotocured polymer was spray-developed with ion-exchange water for 30seconds, to thereby obtain an objective pattern. The pattern had a filmthickness of 5 μm and a resolution of 10 μm, and the sensitivity of thecomposition as evaluated on the basis of the UGRA step tablet was 5.

[0067] The photosensitive composition was stored at 40° C., andvariation in patterning characteristics were evaluated. The resultsindicated that no variation in patterning characteristics were observedeven after the composition had been stored for two weeks. Thephotosensitive composition was subjected to flash point measurement in aCleveland-open manner, and the results indicated that no flash point wasidentified.

Example 3

[0068] To the polymer solution (C) (100 g) which had been obtained inSynthesis Example 3, a 10% aqueous solution (6.8 g) of NaOH serving asan alkali agent for neutralization;1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one(Irgacure 2959, product of Ciba Specialty Chemicals) (2.5 g) serving asa photopolymerization initiator; and ion-exchange water (50 g) wereadded, to thereby prepare a photosensitive composition.

[0069] The thus-prepared photosensitive composition was applied to ametal substrate by means of a spin-coater and dried in a clean oven at80° C. for 20 minutes, followed by cooling to room temperature. Thecoating was exposed to ultraviolet light from an ultra-high-pressuremercury lamp having an illuminance of 2.5 mW/cm² for a dose of 1350mJ/cm², through a mask having a predetermined pattern. Subsequently, thephotocured polymer was spray-developed with ion-exchange water for 30seconds, to thereby obtain an objective pattern. The pattern had a filmthickness of 5 μm and a resolution of 15 μm, and the sensitivity of thecomposition as evaluated on the basis of the UGRA step tablet was 7.

[0070] The photosensitive composition was stored at 40° C., andvariation in patterning characteristics were evaluated. The resultsindicated that no variation in patterning characteristics were observedeven after the composition had been stored for two weeks. Thephotosensitive composition was subjected to flash point measurement in aCleveland-open manner, and the results indicated that no flash point wasidentified.

Example 4

[0071] To the polymer solution (A) (100 g) which had been obtained inSynthesis Example 1, a 10% aqueous solution (2.7 g) of NaOH serving asan alkali agent for neutralization;1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one(Irgacure 2959, product of Ciba Specialty Chemicals) (1.8 g) serving asa photopolymerization initiator; polyethylene glycol dimethacrylate(NK-9G, product of Shin-Nakamura Chemical Co., Ltd.) (4.0 g) serving asa polymerizable monomer; Brilliant Green (1.0 g) serving as an aqueousdye; and ion-exchange water (65 g) were added, to thereby prepare aphotosensitive composition.

[0072] The thus-prepared photosensitive composition was applied to ametal substrate by means of a spin-coater and dried in a clean oven at80° C. for 20 minutes, followed by cooling to room temperature. Thecoating was exposed to ultraviolet light from an ultra-high-pressuremercury lamp having an illuminance of 2.5 mW/cm² for a dose of 1350mJ/cm², through a mask having a predetermined pattern. Subsequently, thephotocured polymer was spray-developed with ion-exchange water for 30seconds, to thereby obtain an objective pattern. The pattern had a filmthickness of 5 μm and a resolution of 8 μm, and the sensitivity of thecomposition as evaluated on the basis of the UGRA step tablet was 6.

Comparative Example 1

[0073] To the polymer solution (D) (60 g) which had been obtained inComparative Synthesis Example 1, pentaerythritol triacrylate (15 g),dimethylethanolamine (3.0 g) serving as an alkali agent forneutralization;2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone (Irgacure907, product of Ciba Specialty Chemicals) (2 g) serving as aphotopolymerization initiator; and ion-exchange water (48 g) were added,to thereby prepare a photosensitive composition.

[0074] The thus-prepared photosensitive composition was applied to ametal substrate by means of a spin-coater and dried in a clean oven at80° C. for 20 minutes, followed by cooling to room temperature. Thecoating was exposed to ultraviolet light from an ultra-high-pressuremercury lamp having an illuminance of 2.5 mW/cm² for a dose of 1000mJ/cm², through a mask having a predetermined pattern. Subsequently, thephotocured polymer was spray-developed with ion-exchange water for 30seconds. However, an objective pattern could not be obtained.

[0075] The photosensitive composition was stored at 40° C. for twoweeks, and component separation was identified.

[0076] As described hereinabove, the polymer compound of the presentinvention is produced by adding glycidyl (meth)acrylate in apredetermined amount to a copolymer comprising at least (meth)acrylicacid and at least one of 2-hydroxyethyl methacrylate and polyoxyethylenemono(meth)acrylate. Thus, the polymer compound developable with water;exhibits excellent adhesion to a glass or metal substrate; and hasexcellent acid resistance. The polymer compound is remarkably useful forproducing a photosensitive composition.

What is claimed is:
 1. A polymer compound containing monomer unitsrepresented by formulas (I) to (III):

wherein each of R₁ to R₄ is hydrogen and/or a methyl group; p representsan integer between 1 to 10 inclusive; X represents hydrogen, an alkalimetal, or an ammonium represented by formula (1):

wherein each of R₅ to R₈ represents hydrogen, a C1-C3 alkyl group, or aC1-C3 alkanol group; and a plurality of Xs may be the same or differentfrom one another, the compositional proportions of the monomer unitsfalling within the following ranges: 2 mol %≦1≦73 mol %; 8 mol %≦m≦83mol %; and 15 mol %≦n≦80 mol %.
 2. A polymer compound according to claim1 also containing a monomer unit other than monomer units represented byformula (I) to (III) in an amount of 10 mol % or less.
 3. A method ofproducing a polymer compound containing monomer units represented byformula (I) to (III):

wherein each of R₁ to R₄ is hydrogen and/or a methyl group; p representsan integer between 1 to 10 inclusive; X represents hydrogen, an alkalimetal, or an ammonium represented by formula (1):

wherein each of R₅ to R₈ represents hydrogen, a C1-C3 alkyl group, or aC1-C3 alkanol group; and a plurality of Xs may be the same or differentfrom one another, and the compositional proportions of the monomer unitsfalling within the following ranges: 2 mol %≦1≦73 mol %; 8 mol %≦m≦83mol %; and 15 mol %≦n≦80 mol %, which method comprises adding glycidyl(meth)acrylate in a predetermined amount to a copolymer comprising atleast (meth)acrylic acid and at least one of 2-hydroxyethyl(meth)acrylate and polyoxyethylene mono(meth)acrylate.
 4. A method ofproducing a polymer compound according to claim 3 , wherein at least oneof an N-nitrosophenylhydroxylamine ammonium salt and4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl is employed as apolymerization inhibitor.
 5. A photosensitive composition containing, asa component, a polymer compound as recited in claim 1 .
 6. Aphotosensitive composition according to claim 5 , which contains wateras a solvent.
 7. A photosensitive composition according to claim 5 ,which contains a polymerizable monomer.
 8. A photosensitive compositionaccording to claim 5 , which contains a colorant.
 9. A photosensitivecomposition according to claim 5 , which contains at least one of aphotopolymerization initiator and a photosensitizer.
 10. A patternformation method comprising forming a coating film by use of aphotosensitive composition as recited in claim 5 and developing by useof water; i.e., a neutral developer.